The present invention relates to the control of printing operations on text data produced by a word processor or by a computer running a word processing programme. The device is intended to be connected between an output port of a word processor or computer and an input port of a printer.
In most office situations, where a word processor is being used to prepare letters, it is necessary to print not only the letter but an envelope or label for such an envelope containing the address data which is usually to be found embedded in the text data of the letter. In order to produce both the letter and label or envelope, a secretary normally has to produce two separate documents and carry out two separate printing operations. Some specialist word processing software provides facilities for printing address labels. However, this is normally limited to "mail merge" type programmes which are intended for producing large numbers of similar letters to addresses selected from a database. In such applications, the label or envelopes are printed altogether as a separate print run. The secretary who produces a number of different letters on a word processor usually finds it necessary to resort to a typewriter to prepare the envelopes required. This results in a considerable expenditure of time and detracts considerably from the efficiency that is otherwise available from the use of a word processor.